77 lines
1.3 KiB
C
77 lines
1.3 KiB
C
#include <stdio.h>
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#include <stdbool.h>
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#include <stdlib.h>
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#include <limits.h>
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int main(int argc, char** argv) {
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if (argc != 2) {
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fputs("Usage: ", stdout);
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fputs(argv[0], stdout);
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fputs(" <input file>\n", stdout);
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return 1;
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}
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FILE* file = fopen(argv[1], "r");
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unsigned int safe_count = 0;
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const int max_length = 16;
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char buffer[17];
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int buf_length = 0;
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int line_no = 0;
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while (true) {
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bool first_number = true;
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int last_number = INT_MIN;
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int last_delta = 0;
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bool safe = true;
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int c;
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while (true) {
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c = fgetc(file);
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if (buf_length < max_length && c >= '0' && c <= '9') {
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buffer[buf_length] = c;
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buf_length++;
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continue;
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}
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if (buf_length > 0) {
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buffer[buf_length] = 0;
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int number = atoi(buffer);
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if (first_number) {
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first_number = false;
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} else {
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int delta = number - last_number;
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if (last_delta != 0 && delta * last_delta < 0) {
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safe = false;
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} else if (delta == 0 || abs(delta) > 3) {
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safe = false;
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}
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last_delta = delta;
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}
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last_number = number;
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buf_length = 0;
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}
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if (c == EOF || c == '\n') {
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break;
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}
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}
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if (safe && !first_number) {
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safe_count++;
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}
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line_no++;
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if (c == EOF) {
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break;
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}
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}
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printf("Safe count: %d\n", safe_count);
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fclose(file);
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}
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